The solenoids serve double duty — first, they move pieces of flat “fridge magnet” material close enough to attract iron filings. Their second duty is of course provide a clock tick that will ...

This can be "seen" in two dimensions if iron filings are sprinkled ... efficient if the coil was wound around a metal core, as this helped to concentrate the magnetic field.

Under relatively weak magnetic fields (<1T) they surprisingly stand at attention in solution almost like iron filings arrange ...

A 1/2 inch diameter cylindrical magnet works well. Iron Filings: Available from: Science supply stores like Home Science Tools, Carolina Biological, or Educational Innovations Some craft stores in ...

The solenoids serve double duty — first, they move pieces of flat “fridge magnet” material close enough to attract iron filings. Their second duty is of course provide a clock tick that will ...